Lock.



No. 660,230. Patented Oct. 23, I900.

J. J. TREAT.v

LUCK.

(Application filed Apr. 6, 1900'.)

(No Model.)

UNITED STATES PATENT OFFICE.

JOHN J. TREAT, OF NEW BRITAIN, CONNECTICUT.

LOCK.

SPEGIFICATION forming part of Letters Patent No.

660,230, dated October 23, 1900.

Application filed April 6,1900. Serial No. 11,835. lNo model.)

the art may make and use the same.

The object of this invention is to simplify and cheapen the constructionof locks of the class which require two or more keys to operate them, noone of the keys by itself being capable of so doing. The means by whichthis object is accomplished is shown in the drawings, in which Figure 1is a view of the hack of a lock with some of the parts broken away toshow the construction. Fig. 2 is an edge view of a lock. Fig. 3represents the two sections of the key in side view, showing thedifference in the bittings. Fig. 4 shows in edge view the two parts ofthe key together.

It is often advisable, when two or'more parties are interested inarticles which are kept under lock and key. that the containing packageor its lock be so constructed that the package cannot be opened withoutthe presence of at least two of the parties concerned. Thesafety-deposit box is a case in point, it being customary for both theone who is responsible for the safe-keeping of the box and the owner tohave keys, the lock being so constructed that .neither key will open thebox without the aid of the other. Locks of this kind are generally knownin the trade as guard-key locks, and this name will be used hereofter todesignate such a lock. There are a number of locks uowin the marketwhich fill the requirements, but they are very complicated andexpensive. In many constructions now in use, I believe, two sets oftumblers are provided and are necessary, one set being operated by eachkey, and it is the general construction to have one key, called theguard-key, operate a lockin g device for the bolt of the lock proper,while the other key operates the bolt as soon as the lock-bolt isreleased. It will be evident to one familiar with the lock business thatto make such a construction as is above suggested there are manydifficulties to be overcome and that at the best the arrangement isbound to be intricate and the manufacture and assembling expensive. Bythe invention which I will now proceed to describe I have accomplishedthe desired results and am enabled to produce an effective guard-keylock extremely simple in construction and at a minimum cost.

Referring to the drawings, A denotes the case, B the bolt, C thetumblers, and D the key-guide, of an ordinary lock.

E is the fence on the bolt,which rests against the end of the tumblers 0when the bolt is shot and travels back in the gating b in the tumblerswhen the bolt is withdrawn. This is all according to the ordinaryconstruction of a lock of this class; but it is to be clearly understoodthat my invention is applicable to any and all descriptions of locks,the one illustrated being used because of its simplicity andadaptability for the purpose of illustration.

My invention consists, essentially, in a lock preferably havingbut oneset of tumblers and a compound key H, made up of a series of elements MN, adapted to operate the tumblers of the look only when all of theindependent elements are present and used simultaneously. Each sectionofthe key has individual bittings,the total number of operative bittingson the several sections being equal in number to the number of tumblersin the look. It is preferable to usea key made up of not more than twosections, although it is evident that the number of sections is notessential to my invention. In appearance each section of this compoundkey is itself a key, having a handle, a shank, and bittings. In the keyshown in Figs. 3 and 4 each section has individual bittings X Y, whichare staggered with the bittings on the other sections, this being one ofthe many forms in which my invention may be used. Each section of thekey has certain duties to perform, and these sections must always beused with a certain relation to one another, and in order to insure theproper positioning of the parts I place some kind of a guard,

such as the projection o, on one or more of the parts.

I claim as my invention- 1. A lock-bolt controlled by a single set of Alock-bolt controlled by a slngle set of tumblers mounted upon the samepivot in combination with a plurality ofindependent keys operativesimultaneously side by side, the bittin gs of all of which togetheraggregate in number the number of tumblers in the lock whereby it isnecessary to use the keys together to operate the look.

Signed this 31st day of March, 1900, at New 20 Britain, Connecticut.

JOHN J. TREAT.

Witnesses:

JENNY 'l. HOUGH, H. E. HART.

